GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Wet Mineral Wool

1869farmhouse | Posted in General Questions on

I had a couple pallets of Insul-Fill mineral wool delivered and we had an unexpected rain.  The packages are wrapped in plastic, but certainly not water tight.  I know it’s nothing like fiberglass, but should I be worried about using it?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
    Dana Dorsett | | #1

    How are you intending to use it? Are you installing (blowing) it yourself?

    If it's dry enough to not be an issue with the blower it's just fine to use for open blowing in a vented attics. If it feels wet to the touch installing it in walls with brick veneer or other exterior masonry might be an issue for a late-autumn installation if there's a poly vapor barrier on the wall preventing drying toward the interior, but probably not much of a risk for wood or vinyl sided houses.

    Odds are only the top layer of bags took on any appreciable moisture. You might weigh a few of the top layer bags and compare that to the weight of those on the bottom of the pallet. If they're more than 10% heavier it might make sense to set those aside and defer the decision until later, or open them up and store them in a warm conditioned space for a week or two before using the the suspect bags.

    1. 1869farmhouse | | #3

      Thanks Dana. I will be blowing it myself and 80% will be going into a vented attic space. The other 20% will be blown into an encapsulated attic space. I guess you’re right, both will be allowed to dry the rest of the way. One to the outside and the other dried by conditioned air. Thanks for the reassurance!

  2. Expert Member
    BILL WICHERS | | #2

    I would peak inside the end of one of those bags and feel for dampness. You might be surprised how well protected it is inside the bag. Unless you had a MAJOR amount of rain, you'll probably be OK. If you do find it seems damp, Dana already covered what you need to do in that case.


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |